Loneliness Linked to Worse Memory, but Not Faster Cognitive Decline
In a new study, lonelier older adults performed worse on memory tests, but their performance didn’t decline any faster than people who were less lonely.
Loneliness and social isolation are increasingly recognized as major public health issues, especially in aging adults. A 2023 survey reported that 37 percent of older Americans experienced loneliness, with one in five reporting feeling socially isolated very often. These feelings impact physical and mental health, and in some studies, even increase the risk of dementia.
While it isn’t clear whether these feelings cause these diseases directly, scientists find that many lonely people have multiple other risk factors for dementia, which might explain part of the link.
But some of the research on loneliness is inconsistent, and few studies track individuals over time to see the long-term effects of loneliness. A recent study published in the journal Aging & Mental Health followed over 10,000 older Europeans over the course of six years. People who had higher levels of loneliness at the start had more memory problems compared to those with low or average levels of loneliness. But there might be a surprising silver lining.
“We expected that higher perceived loneliness would be associated with a faster rate of decline over time,” Luis Carlos Venegas-Sanabria, a professor at Universidad del Rosario in Colombia and the study’s lead author, told Being Patient. But the study participant defied this expectation. Loneliness did not lead to faster rates of cognitive decline.
How loneliness affects memory and cognitive decline
The team analyzed data collected between 2012 and 2019 from a longitudinal survey called SHARE, which asked aging Europeans questions about their health. The study included respondents over 65 from 12 countries, including Germany, Spain and Sweden, and grouped the countries into four geographic regions for the analysis. The researchers excluded anyone diagnosed with Alzheimer’s, dementia, or other significant day-to-day impairments from the analysis.
At three time points over six years, study participants received tests that measured how well they remembered a list of ten words, both immediately after seeing them and five minutes later.
To measure the level of loneliness, the participants answered three questions:
- How much of the time do you feel you lack companionship?
- How much of the time do you feel left out?
- How much of the time do you feel isolated from others?
Ninety-two percent of the participants reported average or low levels of loneliness at the start of the study.
The 8 percent who were loneliest were typically older, female, and had other health issues, including a high prevalence of depression, high blood pressure, and diabetes. All of these factors increase the risk of dementia.
The participants who were loneliest had more trouble remembering the word list immediately after seeing it, as well as five minutes afterward. However, their memory abilities did not deteriorate any faster than those who reported average or low levels of loneliness.
One of the major limitations, according to Venegas-Sanabria, is that the researchers only measured loneliness once at the start of the study. It doesn’t consider whether participants maintain their level of loneliness throughout.
“While our specific analysis focused on the impact of loneliness levels measured at the start of the study,” he said, “other research has suggested that the duration of loneliness may influence the rate of memory decline.”
Ultimately, the study comes to a counterintuitive conclusion: Loneliness is not necessarily a risk factor for dementia. But Martina Luchetti, a researcher at Florida State University who wasn’t involved in the study, disagrees.
She told Being Patient that the ability to detect cognitive changes over time depends on the methods and the amount of times that memory is measured. In other words, measuring three times over six years might not be enough to detect a real difference. The association with poor memory scores “may reflect reduced cognitive reserve which implies vulnerability” to dementia, said Luchetti.
How to be less lonely
Unlike many major risk factors for dementia, like age or genetics, loneliness is modifiable. Research is currently underway to test whether intervening and providing companionship could lower the risk of dementia down the line. Some prior research suggests that recovering from loneliness is a boon for brain health.
“It’s so important to stay engaged and connected as we age, especially in retirement,” social scientist Kasley Killam told Being Patient. In her book, The Art and Science of Connection, Killam advocates for the 5-3-1 formula to stave off loneliness: Interacting with five different people each week, cultivating three close relationships, and spending one hour a day connecting with others.
“Investing in our relationships benefits our bodies and brains,” Killam said, “not to mention gives our lives meaning and joy”.
FAQs
Current evidence isn’t enough to establish that loneliness directly causes dementia or Alzheimer’s. However, loneliness impacts mental and physical health which could increase dementia risk.
Loneliness is the subjective feeling of being alone while social isolation refers to a lack of social connections or contact with others. Some people are isolated without being lonely and other people may feel loneliness even if they have many social connections.
Unlike many major risk factors for dementia, like age or genetics, loneliness is modifiable. Research is currently underway to test whether intervening and providing companionship could lower the risk of dementia and some prior research suggests that recovery from loneliness is a boon for brain health.
